class StageDisplay implements StageObserver {
    private static final String[] STAGE_NAMES = {
            "受精卵", "桑椹胚", "囊胚", "原肠胚", "成熟"
    };

    @Override
    public void onStageChanged(int newStage) {
        if (newStage < STAGE_NAMES.length) {
            System.out.println("进化到: " + STAGE_NAMES[newStage]);
        }
    }
}
